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Data Communication
Overview Data Communication will be no match for you if you pay attention to the DataComm Oracle. If you become overwhelmed just keep things simple and always remember, most devices are merely clusters of smaller devices. Buses: Connections Within a Device *'Bus' **Subsystem that transfers data between computer componnets inside a computer or between computers. 10/14/10 Slide 7 *Types of Buses 10/14/10 Slide 10 **Parallel Buses: carry data words in parallel on multiple wires.IEEE 1284 "printer port, SCSI, PCI **Serial Buses: carry data in bit-serial form. ***USB (Universal Serial Bus), FireWire, Ethernet, T1, Serial AT *Wikipedia Bus Link Peripherals: Connected Devices *Three Main Connection Methods 10/14/10 Slide 12 **Interrupt: a device like a mouse of a keyboard, which will be sending very little data. **Bulk: a device like a printer, which receives data in one big packet. A block of data is sent and then verified to make sure it is correct. **Isochronous: a streaming device (such as speakers), data streams between the device and the host in real-time, and there is no error correction. Closer Look at Serial Buses: USB & Firewire *How USB Works **Divides available bandwidth into frames. 10/14/10 Slide 17 ***Controlled by host ***1500 bytes per frame ***Data is sent as packets **Inside a USB cable 10/14/10 Slide 18 ***Two wires for power (red) and ground (brown), and a twisted pair of wires (yellow and blue) to carry data. *USB bit rates 10/14/10 Slide 21 **USB 1.0 - 1.4 Mbit/sec **USB 1.1 - 12 Mbit/sec **USB 2.0 - 480 Mbit/sec **USB 3.0 - 5 Gbit/sec *USB 3.0 10/14/10 Slide 20 **Released November 17, 2008 **AKA SuperSpeed USB **Uses parallel optical cable **Backward compatible with 1.0 and 2.0 **Commercially available in 2010 *Firewire 10/14/10 Slide 24 **IEEE 1394 High Speed Serial Bus **Firewire 400 is the older protocol **There is also 800, S1600 and S3200 **400- 3200 Mbits/sec *USB vs. Firewire Comparison Chart 10/14/10 Slide 25 *USB vs. Firewire Video Demonstration 300px Other Buses *HDMI: High Definition Multimedia Interface **Replaces coaxial (analog) and DVI (digital). 10/14/10 Slide 27 **Contains 6 connector pins - 3 audio and 3 video. 10/14/10 Slide 28 **Wikipedia HDMI Link *VGA: Video Graphics Array **Lowest common denominator for graphics on computers. 10/14/10 Slide 30 *SATA: Serial Advanced technology Attachment 10/14/10 Slide 31 **7 connectors - 3 ground, 4 data lines **More efficient space use Data Communication Equipment (DCE) *Codecs *Terminal Adapters (TAs) **Interface adapter for connection one or more non-ISDN devices to an ISDN network. 10/14/10 Slide 49 *Channel Service Units (CSUs) and Data Sevice Unites (DSUs) **Interface the user environment and digital local loop. 10/14/10 Slide 49 *Modems **Needed to interface with the analog local loops standardized at ITU, v series 10/14/10 Slide 50 ***Include compression and error correction. **How Stuff Works Explanation on Modems **Data Modulation 10/14/10 Slide 53-55 ***Amplitude Shift Keying (ASK) ***Frequency Modulation Keying (FSK) ***Phase Modulation Keying (PSK) **Modem Speeds 10/14/10 Slide 51 ***300 bps - 1960s through 1983 ***1200 bps - gained popularity in 1984 and 1985 ***9600 bps - first appeared in late 1990 ***56 Kbps - became the standard in 1998 ***ADSL max of up to 8 Mbps - gained popularity in 1999 *Modern Modems 10/14/10 Slide 56 **Increase bit rate within standard bandwidth of telephone line **Use multiple signal levels **Vary both amplitude and phase - known as quadrature amplitude modulation (QAM) [[Data Networks|'CONTINUE...' ]] [[TC201 Giga Wiki|'MENU' ]] References